1. Field of the Invention
The invention is related to an electric apparatus, and more particularly to an electric apparatus having a humidity sensing function.
2. Description of Related Art
Humidity indicator card is a common simple-type indicator for determining if humidity of an environment exceeds a normal value. However, humidity indicator card requires observation by a user to obtain if humidity of an environment exceeds normal. Therefore, humidity of an environment may exceed normal for a period before being noticed; in that case, the object monitored by such humidity indicator card may have had been damaged. In addition, humidity indicator card contains several polluting chemical components, thereby failing to comply with the European Union (EU)'s environmental protection requirements. As a result, application range of humidity indicator card is limited.
U.S. Pat. No. 4,638,346 discloses a field effect transistor-type moisture sensor. US20100071460 discloses that characteristics of a channel layer of a field effect transistor may be influenced by humidity of an environment. US20100307238 discloses a field effect transistor-type humidity sensor, which changes its capacitance parameters according to changes in humidity so as to achieve the purpose of humidity detection. U.S. Pat. No. 4,464,647 discloses a metal oxide semiconductor humidity sensor. U.S. Pat. No. 7,571,637 discloses a real-time moisture detection circuitry.